Mix sugar, flour, nutmeg, and cinnamon together in a bowl.
Pour peaches into the bottom of a glass 9x13-inch baking dish. Sprinkle sugar mixture over peaches and mix well. Scatter 1/2 of the butter chunks over the peach mixture. Arrange pastry strips over peach mixture in a crisscross or striped pattern. Scatter remaining butter chunks over pie pastry.
Bake in the preheated oven until crust is golden brown and crisp, 30 to 40 minutes.